Validation of the Automated Readability Index: A Follow-Up
J. Peter Kincaid, Leroy John Delionbach · Human Factors The Journal of the Human Factors and Ergonomics Society · 1973
The Automated Readability Index (ARI) is a measure of reading difficulty level of narrative material. In computing the ARI a modified electric typewriter is used to compute average word and sentence length. One hundred and ten Army National Guard personnel read passages of technical material at three levels of reading difficulty, 8th, 12th, and 16th grades, as measured by the ARI. Tested reading comprehension was lower for material written at the highest level of difficulty (16th grade), and was significantly correlated with scores previously obtained on the Armed Forces Qualification Test, which can be considered a measure of general reading ability.